4. How to Measure
MATHEMATICAL METHOD
A. The main metric scale is read first and this shows that there are 13
whole divisions before the 0 on the hundredths scale. Therefore, the first
number is 13.
B. The’ hundredths of mm’ scale is then read. The best way to do this is to
count the number of divisions until you get to the division that lines up
with the main metric scale. This is 21 divisions on the hundredths scale.
C. This 21 is multiplied by 0.02 giving 0.42 as the answer (each division on
the hundredths scale is equivalent to 0.02mm).
D. The 13 and the 0.42 are added together to give the final measurement
of 13.42mm (the diameter of the piece of round section steel)
5. COMMONSENSE METHOD
Alternatively, it is just as easy to read the 13 on the main scale and 42 on
the hundredths scale. The correct measurement being 13.42mm.
Example 1
11. The proper way to use a micrometre is to hold it in your dominant hand.
Grasp the thimble between your thumb and index fingers.
Place the C-shape of the frame against your palm.
Finally, partially wrap your pinkie or ring finger within the inside of the
frame.
Hold the object to be measured in your non dominant hand.
12. Quick tips:
+ Support the weight of the micrometre in your palm so you can twist the
thimble or ratchet by rubbing your thumb and index fingers.
+ Don’t insert your pinkie or ring finger into the frame so much that you
obstruct the object to be measured.
+ Don’t cover the sleeve with your palm or you won’t be able to see the
measurement.